The Elan Valley damsThe Claerwen dam

The location of
the Elan Valley dams
and reservoirs
is shown on thesketch map.

Increasing need for
water
The severe drought of 1937 served to give warning of the increasing
need for much greater water storage capacity. The three dams
proposed for the Claerwen Valley as part of the original Elan
Valley waterworks scheme of 1892 had not been built, apart from
the base of the dam at Dol-y-Mynach
which had to be constructed early because of its location below
the top water level of the Craig Goch reservoir.

The
wide expanse
of the upper
Claerwen Valley
before being
submerged

The intention of James
Mansergh was that the dams on the Claerwen, though included
in the initial plans, would be built in later years when Birmingham's
needs increased.
It was to be quite a long time before further use was to be made
of the potential of the River Claerwen for increasing the reserves
of water to be made available for delivering supplies to the
city of Birmingham. Further construction work in this valley
was to be substantially delayed by the two major wars after the
completion of the Elan Valley scheme in 1907.

The newly built
Claerwen dam
in 1952

By kind permission of
Radnorshire Museum,
Llandrindod Wells

Proposals for a large
new dam in the upper Claerwen Valley were at an advanced stage
by early 1939, but the Second World War meant that the demands
of wartime production itself put even greater strains on the
existing water supplies.
The increasingly urgent calls for a new dam and reservoir on
the Claerwen were to be reactivated soon after the end of the
war. Progress in civil engineering techniques and in mechanisation,
however, meant that much larger dams could be built by this date.

It had again been necessary to obtain the authority of Parliament
before proceeding with the new dam, since the original Birmingham
Corporation Water Act 1892 permitted construction of the
three smaller dams as specified in the original scheme.